This error, usually preceded with the message "Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client", means that the bitness of Outlook and FileMaker don't match. In order for Outlook Manipulator to work properly, both applications need to be either 32-bit or 64-bit, but not a mix of the two. Please make sure that the bitness of the both FileMaker and Outlook match and try again.